Smart sensor probes that can predict landslides

15:42, September 25, 2010

University experts in electronics and geography in the UK expect to have sensor probes that can predict the onset of landslides by the end of this year.

They are Dr Kirk Martinez, at Southampton University's School of Electronics & Computer Science, and Professor Jane Hart in the university's School of Geography.

Both these leading researchers have been funded by the US-based National Oceanic & Atmospheric Administration to develop sensors to monitor erosion rates during southern California's stormy season this winter.

Six hand-size sensors have been placed in Los Laureles canyon in Mexico - about two miles (3.2km) from the US border - an area that is repeatedly under water because of torrential rain and mud slides. The canyon leads into the Tijuana River Estuary, a national reserve.

"Nobody has ever tried putting radio-based sensors into slopes before," said Dr Martinez. "We are very close to having a miniaturised version that measures light, conductivity and tilt."

He explained that the canyon area has no proper drainage system, and very poor-quality housing that faces massive flooding problems. "The streets are not paved and, when water flows, it picks up sediment and becomes quite aggressive," said Dr Martinez.

To help the area's scientists prevent landslides, he and other team members put the probes in place to measure the ground's tilt, moisture, temperature and pressure.

In addition, the rain and mud that can flow north across the border can directly impact the Tijuana coastal estuary, between California and Mexico. The estuary is a wetland that supports many rare and endangered species, one of the few salt marshes remaining in southern California and an important area for 370 species of migratory and native birds.

The sensor probes take a reading every few minutes monitoring factors such as soil wetness and movement. Every hour the data details are fed directly to US company HoundSystems at San Diego and to Southampton's geography department for analysis.

"One challenge now is to get them measuring more and to have them become more active when a storm is predicted," added Dr Martinez who developed sensor probes to monitor glacier movements in 2003.

"We are already getting very good signs that we are getting a sense of the changes in sediment and soil through the sensors. The next move is trying to predict when things begin to change so that people living nearby can have early warnings of storms and landslides," he said.

According to the researchers, these sensors will be suitable to predict sudden landslides, particularly common in India and Asia and which cause mass devastation, claiming hundreds of lives and leaving millions homeless. They could also be used to predict flooding in the UK.

All of the probe electronics and fittings are designed and built in-house at Southampton University's School of Electronics & Computer Science.

Wireless sensor networks are an excellent technology to develop for environment sensing because they can run from battery power for many years, interlink to achieve long radio range and can use modern sensors easily.

Rather than sampling and sending data continuously, they are programmed to work together and save power during "boring" times; also, they have been successfully used to measure things never seen before.

The probes run from high-energy lithium batteries and "sleep" most of the time and which is how they can operate for many years without operator intervention - expensive in the mountains, impossible under glaciers, explained Dr Martinez.

He added: "With a new grant from the Leverhulme Trust we will be advancing the technology to detect ice quakes in Iceland and are currently recruiting."